Search

The topography and landforms of Guizhou Province in China are complicated, and the climatic conditions of heavy precipitation make landslide disasters in Guizhou Province occur frequently. To avoid damage to people's lives and economic property caused by disasters, a reliable early landslide identification method and landslide monitoring method are urgently needed. Traditional landslide identification and monitoring methods have limitations. InSAR technology has unique advantages in large-scale landslide identification and monitoring, but landslide identification results based on a single deformation value are one-sided. Therefore, this paper uses Sentinel-1A radar satellite image data and uses InSAR technology and optical remote sensing technology to carry out large-scale surface deformation monitoring and identification of dangerous deformation areas in Liupanshui City, Tongren City, Guiyang City and other regions in Guizhou Province. The potential landslide identification methods based on the time series normalized difference vegetation index and landslide development environment elements are combined to investigate hidden landslide hazards in the study area. In this paper, time series InSAR technology is used to monitor three key landslides in Jichang Town, Yujiaying and Fana, to grasp the movement status of the landslide in time. The method of landslide identification and monitoring in this paper is of great significance for disaster prevention and management in Guizhou Province. [ABSTRACT FROM AUTHOR]

Over the past few decades of rapid development, China has always attached great importance to the redevelopment of rural areas. Since the 19th National Congress of the Communist Party of China, the rural revitalization strategy proposed at the meeting has always received extensive attention. In 2019, the Chinese central government released a document on its rural revitalization strategy. In the document, Guizhou Province was listed as a key area to receive focus on pursuing rural revitalization. Meanwhile, the Guizhou government also formulated The Implementation Opinions on the People's Government of Guizhou Province's Rural Revitalization Strategy. The aim of this paper is to try to establish a model according to the rural revitalization strategy proposed by the Guizhou government and extracts the main influencing factors from its analysis. Through the analysis of the data collected during the process of the rural revitalization, the paper undertakes a deep analysis of the evaluation and studies an optimized approach to the revitalization to provide a referenced review for other villages. [ABSTRACT FROM AUTHOR]

Rural farmland transfer is a key factor in the successful implementation of targeted poverty alleviation strategies in China. In this paper, a multidimensional index system with 15 indicators from five dimensions, namely, natural, human, physical, financial, and social capital was established. It analyzed the effect of farmland transfer on poverty alleviation under four typical poverty alleviation models implemented in a karst area in China by using Propensity Score Matching (PSM) and Difference-in-Difference (DID) to analyze 467 rural households questionnaire responses from five representative villages in Guizhou Province. The results show that different models had different effects on poverty reduction. In the model of "three changes" + relocation for poverty alleviation + rural tourism + poor households, farmland transfer was the most effective in poverty alleviation, as attested by its average treatment effect on the treated (ATT) value of 0.44. Rural households' nonfarm income increased significantly to develop rural tourism after relocation from inhospitable areas. In the model of "farmland lease/shareholding" +cooperative + enterprise + poor households, farmland transfer had a moderate effect on poverty alleviation, with an ATT value of 0.06. Its effect on the total income of rural households was the lowest among the four models. This study's results can provide a theoretical reference for solidifying the benefits of poverty alleviation and rural revitalization strategies in karst areas. [ABSTRACT FROM AUTHOR]

The northern Guizhou coalfield exhibits complex geological conditions and well-developed structures. Hard rock formations are damaged by faults, causing frequent water inrush accidents. To study the damaging effect of faults on roof key strata and the mechanism of water inrush accidents, this paper chose the 5914 coal mining faces of the Longfeng coal mine as the engineering background, determined the water inrush source and key strata through field investigation, hydrochemical analysis, and theoretical calculation, and used RFPA-flow numerical simulation software to simulate the hydraulic coupling effect. The characteristics of the shear stress, damage degree, and hydraulic gradient were analyzed, and finally, the high-density electrical method was employed for simulation verification. The results indicated that the key stratum can control water inrush, but under the influence of faults, the roof forms multiple separation layers, and several sudden increases in displacement occur (the sudden jump phenomenon). A stress concentration area is formed in the head-end tunnel through the fault, and the number of AE events increased to 1150. The water-force gradient exhibits a uniform local large-scale evolution process, and finally, the height of the water-conducting fracture reaches 60 m through the aquifer. This height is 3 times that without fault influence. The numerical simulation results are consistent with the theoretical calculation and field analysis results, which verifies that the fault imposes a highly significant weakening effect on the key stratum, providing data support for later engineering. [ABSTRACT FROM AUTHOR]

Chestnut rose is an endemic plant in Guizhou Province, China, also known as seedless prickly pear, rich in mineral elements, vitamin C, and flavonoids. With chestnut rose as the main raw material, with grapes, apples, and other fruits as auxiliary ingredients, through the technical process of deastringency, sterilization, fermentation, blending, and other technical processes to obtain the composite beverage, known as a chestnut rose jiaosu compound beverage, it is hereinafter referred to as CRJCB. The CRJCB fermented from chestnut rose juice is nutritious and has a variety of health effects, and the flavor is unique, with good color, aroma, and taste, which is a new type of beverage. However, at present, the fermentation related technology of CRJCB is not perfect, resulting in its low quality, which seriously restricts the industrialization development of CRJCB. In order to improve the quality of the jiaosu compound beverage, probiotics such as Lactobacillus delbrueckii subsp. Bulgaricus, Lactobacillus casei, Lactobacillus royale (Lactobacillus reuteri), Lactobacillus acidophilus, and Streptococcus thermophilus, etc., were used. The chestnut rose as the main raw material was used for the fermentation, and grapes, apples, and sugar were used as auxiliary materials to carry out the research on the fermentation of single or mixed probiotics. The key fermentation processes affecting the quality of the jiaosu, such as juice preparation, deastringency of chestnut rose juice, fermentation temperature and time, sugar addition, and taste mixing of the jiaosu, were optimized. The optimized ratio, fermentation process parameters, and strains of probiotics of compound beverage with chestnut rose jiaosu, with high quality, were obtained. The experimental results showed that the SOD enzyme activity value was 167.7 U·ml−1, the vitamin C content was 1154.5 mg/100 mL, the soluble solids content was 5.80%, and the nitrite content was 89.8 mg/kg in the compound beverage with chestnut rose jiaosu, obtained by using the optimized ratio and fermentation process parameters proposed in this paper. The development and utilization of chestnut rose resources provide a new idea and is of great significance in promoting the development of the chestnut rose industry. [ABSTRACT FROM AUTHOR]

Pusa village is located in the karst mountain area of Nayong County, Guizhou Province, China. Laoyingyan mountain rock is gently dipping, the upper part consists of hard rock formations, and the lower part is made up of soft rock composed of 3 coal seams. On August 28, 2017, a massive landslide occurred in this area, resulting in 82,3000 m3 of debris, which resulted in significant casualties and brought up the malaise in society. In this paper, the geological conditions and long-term mining activities in the study area are analyzed by field investigation. The base friction tests and numerical models are used to simulate and analyze the failure and deformation process of Pusa collapse to accommodate the research on the deformation and failure mechanism of the slope and provide better prevention and treatment suggestions. The results show that the Pusa collapse can mainly be attributed to unique geological conditions, underground mining activities, and the topography of the slope. The intensified mining activities promoted the development of fractures and cracks in the slope, resulting in unstable upper slopes. The failure process of the Pusa collapse can be summarized into four-stage: the development of goaves roof deformation, the crest of the slope cracks, intensification of deformation, and occurrence of collapse. The upper slope with high strength rock developed crack-toppling failure. Meanwhile, the upper slope with low strength rock developed subside-crack-sliding failure, and those two failures together contributed to the mechanism of Pusa collapse. Slope deformation and failure mechanism can be summarized as subside-crack-toppling-shear sliding type. [ABSTRACT FROM AUTHOR]

Due to the transfer of Lannigou gold mining from shallow to deep, a series of stability problems of surrounding rock have been caused. The drilling pressure relief technology has unique advantages in the control of mine pressure in high-stress roadways. In order to explore the damage effect of borehole pressure relief technology on rock, uniaxial compression and acoustic emission tests were carried out on siltstone specimens with borehole diameters of 8 mm, 12 mm, and 16 mm, respectively, and the acoustic emission signals of the whole process were collected simultaneously to explore the uniaxial compression of siltstone specimens with prefabricated holes in this paper. According to the statistical characteristics of acoustic emission, the damage law of siltstone specimens with prefabricated holes was explored from the microscopic point of view and the damage effect of drilling on siltstone specimens reflected by the acoustic emission phenomenon was revealed. The research results show that there are multiple stress drops before the deformation and failure of the rock sample with prefabricated drill holes; there is a positive correlation between the diameter of the drill hole and the power law index of the stress drop distribution; the acoustic emission activity of the rock during the deformation and failure process can be indirectly reflected the evolution of microfractures; the energy probability density function under different borehole diameters conforms to the power law distribution; the critical exponent obtained by the maximum likelihood estimation has an optimal plateau value, which can accurately characterize the power exponent of the energy distribution; the launch waiting time and aftershock sequence have a good power-law distribution in logarithmic coordinates. The research results provide a certain theoretical basis for the application of drilling pressure relief technology in southwestern Guizhou. [ABSTRACT FROM AUTHOR]

The current paper studies the influencing factors of permeability in shales of the Longmaxi Formation, located in the southern Sichuan Basin, China. The methodologies used in the present study include overburden pore permeability experiments, whole rock analysis and geochemical tests, NMR measurements of fluid saturation, pore size distribution and specific surface area distribution, SEM and extraction of pore structure parameters, and core analysis. The results show the following: (1) high TOC and high maturity generate a large number of organic pores, which may improve the permeability of shale. (2) Mineral composition and rock relative permeability also have influence on permeability to a certain degree, since different minerals have different effects on shale permeability. Clay in the study area has an adverse effect on permeability. The results show that the organic-rich siliceous clay mixed shale facies in this area has the best permeability. (3) A large specific surface area and total pore volume are associated with good shale permeability, while average pore size does not correlate with permeability. A small fractal dimension of pore morphology and simple pore structure result in good permeability, and bedding is the key controlling factor for the anisotropy of shale permeability. (4) Water in shales can influence the permeability of microfractures by binding to clay minerals. Low permeability in shales with high bound water saturation suggests that water and clay mineral absorption may block flow channels, resulting in poor permeability. The purpose of this study is to clarify the influencing factors on shale permeability of the Longmaxi Formation in the study area and to provide a reference for the exploration and development of shale gas in this area of the Sichuan Basin. [ABSTRACT FROM AUTHOR]

In order to better study the propagation law of tunnel blasting in mountain landforms, taking the excavation blasting project of the Yangliu tunnel along the Yinsong expressway in Guizhou as the research object, the propagation law of vibration waves to tunnel blasting under the mountain tunnel was analyzed based on the ABAQUS finite element software and compared with the field monitoring data. The results show the peak vibration velocity of numerical simulation. Generally, the simulation value is slightly larger than the field monitoring value, but the average error of closing speed is less than 25% and the maximum error is less than 45%. The component velocity of surface peak vibration under blasting to load is the largest in the vertical direction. The "cavity effect" formed by the side-passing tunnel wall has the most significant amplification effect on the peak vibration velocity in the X direction of the rock and soil above it, which is about 1.62∼1.85 times and the resultant velocity is enlarged by 1.27∼1.45 times. Blasting vibration waves spread to the surface in the form of spherical waves inside the mountain, causing the vibration center of the surface to move to the area with lower elevation. The "cavity effect" caused by the side-through tunnel and the shift of the surface diffusion center to the lower part together led to the peak velocity of the lower measuring point of the Yangliu tunnel being much higher than that of the higher measuring point. The research results of this paper have certain reference significance in controlling the influence of underground blasting vibration on residential buildings in mountain areas. [ABSTRACT FROM AUTHOR]

Yuanshui River is the third largest tributary of the Yangtze River and one of the four major water systems of Dongting Lake. It originated in Jiguanling, Wu Yun, Duyun City, Guizhou Province, and Pingyue Mountain, Majiang County. It flows eastward to Tuokou Town, Hongjiang city, Hunan Province, where it joins Qushui and is called Yuanshui. Ceramic is the representative of Chinese traditional culture. In the long-term development process, there are many kinds of ceramics with brilliant history and exquisite skills. At present, when the traditional national culture is seriously lost, protecting and developing the traditional national ceramic skills in Yuanshui River Basin will help us to fully understand the traditional national culture in Yuanshui River Basin, carry forward the excellent traditional national culture in Yuanshui River Basin, and enhance national self-confidence. Based on this, this paper analyzes the inheritance and innovation of traditional ceramic crafts in Yuanshui River Basin and constructs the mechanical characteristic model of ceramic crafts with data simulation method. Combine the innovative consciousness of keeping pace with the times with the spirit and quality of the times to realize the all-round development of ceramic art. [ABSTRACT FROM AUTHOR]

A reliable and effective qualitative near-infrared (NIR) spectroscopy discrimination method is critical for excellent model building, yet the performance of models built by these methods is highly dependent on valid feature extraction. The goal of feature selection is to associate the selected variables with the property of interest, which many have done successfully. However, many of selection methods focus only on strong association with the analytes or properties of interest, neglecting correlations between variables. A variable selection method based on a fast nondominated-ranking genetic algorithm (NSGA-II) was proposed in this paper for qualitative discrimination of NIR spectra. The method had two objective functions: (1) maximizing the sum of ratios of interclass variance to intraclass variance, (2) minimizing the sum of correlation coefficients between the selected variables. FT-NIR spectra of a total of 124 tobacco samples from different origins and parts in Guizhou Province, China, were used as the experimental objects, and the part-grade discrimination models of tobacco leaves were established by combining this method with partial least squares-based discriminant analysis (PLS-DA), and compared with PLS-DA model based on the full spectrum. The results showed that the performance of PLS-DA model with the NSGA-II was improved, with a comparable or better correct discrimination rate and reasonable discrimination rate, and could discriminate different parts of the tobacco leaves well. It indicates that the NSGA-II can select a few and effective feature variables to build a high-performance qualitative discrimination model and is proved to be a promising algorithm. In addition, the method is not designed exclusively for spectral data. It is a general strategy that could be used for variable selection for other types of data. [ABSTRACT FROM AUTHOR]

In order to study the influence of roof stress and fracture distribution characteristics on the stability of stope surrounding rock under repeated mining in close-distance coal seams, the research background of this paper is the close-distance coal seam mining of a mine in Guizhou province, China. The dynamic evolution characteristics of stope roof caving and the stress environment change law under repeated mining are studied by using the method of similar simulation experiment, numerical simulation, and field verification. The results show that the roof stage under repeated mining can be divided into four stages: normal mining, roof deterioration, end face roof leaks, and support crushing. The tip-to-face distance, support height, and support working condition are the main influencing factors in end face roof control. The main reason for the support crushing is that the roof above the support is broken, the main roof cannot form the self-stable structure, and the support force is insufficient. The roof dynamic load is high, and the subsidence of the end face roof is large, which is prone to roof caving during the stope roof weighting. Moreover, the roof weighting is frequent under repeated mining, which leads to the broken roof and the support cannot be supported, resulting in the occurrence of the support crushing accident. The control strategies for stope roof under repeated mining are provided based on the thorough study findings. The working face 17101 roof is successfully controlled by the aforesaid procedures, which provides the foundation for the management of stope surrounding rock under repeated loading. [ABSTRACT FROM AUTHOR]

The exploration target at different depths through the ground-airborne frequency domain electromagnetic method (GAFDEM) is detected by transmitting waveforms at different frequencies. When taking these different depths into detail, arbitrarily distributed frequencies are needed. However, the current transmitting waveforms are mostly in a fixed frequency ratio or frequency difference, which fails to meet the requirements of exploration accuracy and efficiency at the same time. Therefore, as a solution to this problem, this paper proposes a transmitting waveform design method based on selective harmonic eliminated pulse width modulation (SHEPWM) technology. In the SHEPWM method, three transmitting waveforms with the desired spectrum are obtained by directly controlling the switching angles of a binary sequence with an artificial neural network algorithm. Firstly, our study puts forward the basic theories and principles of the full-periodic asymmetric SHEPWM waveform. Secondly, the study, through simulation, realizes the pseudorandom, depth-focused, and layer-identification waveform with different detection depths. Finally, the application of the proposed SHEPWM waveform to the geological survey in Kaili City, Guizhou Province, proves the correctness and feasibility of this proposed method. [ABSTRACT FROM AUTHOR]

The drought resistance mechanism of typical mosses in the karst area was studied, and the water and photosynthetic physiological adaptation of mosses to karst environmental change was analyzed in this paper, which provided the basis for the restoration and control of karst rocky desertification ecological environment. Three superior plants in the rocky desertification area of Guizhou province were selected; they are, respectively, Erythrodontium julaceum (Schwaegr.) Par., Barbula unguiculata Hedw., and Bryum argenteum Hedw. Results show that the three kinds of plant rock mosses of leaf water potential (Ψs), free water content ( V a ), total water content, and relative water content (RWC) decreased; bound water ( V s ), water saturation deficit (WSD), and V s / V a ratio increased; transpiration rate (Tr) fell slightly, under drought stress. The physiological indexes of water have different degrees of recovery after rehydration. The total chlorophyll content shows a trend of first increasing followed by falling and then rising. RWC was negatively related to qN and positively related to F v / F m , yield, ETR, and qP. After rewetting, the fluorescence parameters are returned to average level under mild-to-moderate stress. At the same time, it is hard to get back to the control level under severe pressure. The water use efficiency (WUE) decreased with stress and recovered to different degrees after rehydration. [ABSTRACT FROM AUTHOR]

Stability control for soft and broken surrounding rock of roadways is one important segment of mining support. Taking 1412 Roadway of a mine in Guizhou province as a research background, this paper studies the large deformation of surrounding rock and the failure of bolts and cables. The deformation and failure mechanism are analyzed by related theoretical analysis and field survey. Then, the feasibility of the composite controlling scheme, bolts and cables + grouting + steel tube concrete support, is verified by theoretical analysis, numerical simulation, and industrial test. Following results can be obtained: main reasons leading to the deformation of surrounding rock and the failure of cables and blots in the roadway are low strength and poor self-stability of surrounding rock, complex stress environment, low support resistance, and lack of reinforced support in crucial supporting sites; the control scheme can reduce the surrounding rock deformation by 40%, which meets the requirements of field application so that this practice can provide some guidance for other similar projects. [ABSTRACT FROM AUTHOR]

Environmental prediction is one of the crucial means for social sustainable development. Based on the continuous sampling of atmospheric precipitation in Guanling County, Guizhou Province, China, from March 2016 to February 2017, and combining the reanalyzed data of the National Centre for Environmental Prediction/National Centre for Atmospheric Research with the Hybrid Single-Particle Lagrangian Integrated Trajectory model, this paper analyzed the variations of δ2H and δ18O in precipitation at the synoptic scale in the Guanling region. The results showed that the variations of δ2H, δ18O, and d-excess values in precipitation exhibited remarkable seasonal variability. The stable isotopic values in precipitation in the winter half-year were higher than those in the summer half-year. The meteoric water line of the winter half-year was close to the annual meteoric water line. The results showed that there was more than one fundamental source of moisture. It was affected by the winter monsoon period, which is longer than the summer monsoon period, so the local evaporation of water vapor participating in the water circulation had a greater impact. With the increase of precipitation, the intercept and slope of the meteoric water line gradually decreased, which indicated that the secondary evaporation was weak under the effect of stable isotope subcloud cluster. The correlations of precipitation δ18O with temperature T and precipitation P vary with time scales. As the time scale decreased, the correlation between δ18O and the temperature and precipitation improved. When P ≤ 5 mm and 10°C < T ≤ 30°C, the most sensitive changes in stable isotopes were observed. In the study area, the backward trajectory model showed that the moisture in the winter half of the year was mainly from the transportation of the westerlies wind, replenishment, and local reevaporation of near-source ocean water, while the water in the summer half of the year mainly came from the transportation of water from the ocean at low latitudes. [ABSTRACT FROM AUTHOR]

Aroma compounds are one of the most important components in tea, as well as an important indicator for its quality. In this paper, using HS‐SPME/GC‐MS method, we established the fingerprint for aromatic components in green tea produced in Guizhou Province, China. In this fingerprint, there are nine volatile aromatic components which have significant correlation with the quality scores of green teas' aroma (p <.05). They contain ethers and aldehydes (dimethyl sulfide and phenylacetaldehyde) of aromatic compounds, and alcohols and esters (1‐penten‐3‐ol, linalool, phenethyl alcohol, geraniol, and Methyl salicylate) of aliphatic compounds, and pyrrole compounds of heterocyclic compounds (3‐ethyl‐1‐pyrrole and 1‐ethyl‐2‐carbaldehyde‐1‐pyrrole). The Regression Model has been established for predicting evaluation scores of green teas' aroma. A good result was obtained via verification, indicating that GC‐MS is a feasible way to analyze key volatile aromatic components in green tea, which also can be used to predict quality scores aroma and different grades. Practical applications: The aromatic components of tea are considered as the important indicator for evaluating the quality of green tea. We can use GC‐MS and other technologies to determine the representative aroma substances in green tea that can evaluate the quality of green tea. In this way, we can use the instrumental analysis method of the aromatic components to assist the traditional sensory evaluation, which make the green tea quality evaluation results more scientific. [ABSTRACT FROM AUTHOR]

To reveal the effect of confining pressure on the mechanical properties and rupture modes of quartz-bearing shale, the shale core of the no. 3 block of Fenggang, Guizhou Province, China, was analyzed by nuclear magnetic resonance, polarized light microscope thin section observation and identification, and core X-ray whole-rock minerals diffraction analysis to determine the distribution of shale minerals in the Niutitang Formation. On the microscale, based on digital image processing technology, this paper characterizes the nonuniformity of minerals in shale, a numerical model that can reflect the true microstructure of shale. Then, the failure process of shale under different confining pressures was simulated. The results show that when the shale is loaded with vertical displacement under different confining pressures, the compressive strength and elastic modulus of the sample change significantly. The failure mode can be roughly divided into three types: the inverted V-shaped (0 MPa, 2 MPa, and 4 MPa), V-shaped (6 MPa and 8 MPa), and inverted Z-shaped (10 MPa). Since the development of fractal theory provides a new space for studying the damage and fracture of rocks, the damage evolution and failure process of shale can also be regarded as the fractal process of cracks, in which the fractal dimension is the core parameter. The calculation is different under different stress levels. The fractal dimension under the condition of confining pressure shows that the value of the fractal dimension is greatly affected by the effect of confining pressure. When the fractal dimension is higher, the fracture mode is more complicated, and the internal damage degree is more serious. The research results provide important theoretical guidance for shale gas fracturing production. [ABSTRACT FROM AUTHOR]

Guizhou is one of the most important black tea producing areas in China. The purpose of this study was to explore the characteristic flavor compounds of Guizhou black tea and investigate the influence of environmental factors on the formation of black tea flavor components. In this study, HS-GC-IMS was used to identify 143 compounds from black tea samples. OPLS-DA was employed to analyze the data, effectively distinguishing black tea from different origins. A total of 83 significant flavor compounds were selected as potential markers using the VIP variable selection method and OAV screening. Cluster analysis was used to identify the characteristic flavor compounds in black tea samples from different origins. In addition, by investigating the climate environment of various production regions and analyzing the volatile components along with stable C and N isotope ratios of samples, it was discovered that the development of volatile components in black tea could be significantly influenced by ambient temperature and light. In regions with higher temperatures, the concentration of volatile components with floral, fruity, and sweet aromas is higher, resulting in a more intense aroma in black tea. In regions with low ambient temperatures but strong sunlight, black tea contains higher levels of components that give it a fresh and nutty aroma. As a result, the aroma of black tea is relatively elegant and fresh. At the same time, it was found that the stable isotope ratios of C and N in black tea were also significantly affected by ambient temperature and were positively correlated. This study introduces a fresh perspective for the comprehensive examination of Guizhou black tea, offering theoretical guidance for optimizing planting conditions and enhancing product quality. Its positive influence on promoting the development of the Guizhou black tea industry is noteworthy. [ABSTRACT FROM AUTHOR]

Real-time expressway traffic flow prediction is always an important research field of intelligent transportation, which is conducive to inducing and managing traffic flow in case of congestion. According to the characteristics of the traffic flow, this paper proposes a hybrid model, SSA-LSTM-SVR, to improve forecasting accuracy of the short-term traffic flow. Singular Spectrum Analysis (SSA) decomposes the traffic flow into one principle component and three random components, and then in terms of different characteristics of these components, Long Short-Term Memory (LSTM) and Support Vector Regression (SVR) are applied to make prediction of different components, respectively. By fusing respective forecast results, SSA-LSTM-SVR obtains the final short-term predictive value. Experiments on the traffic flows of Guizhou expressway in January 2016 show that the proposed SSA-LSTM-SVR model has lower predictive errors and a higher accuracy and fitting goodness than other baselines. This illustrates that a hybrid model for traffic flow prediction based on components decomposition is more effective than a single model, since it can capture the main regularity and random variations of traffic flow. [ABSTRACT FROM AUTHOR]

This paper intends to examine the coupling and coordination degree (CCD) between the urbanization and ecological environment in Guizhou, China. The entropy weight method and coupling effect model were used to calculate the CCD between the urbanization and ecological environment of Guizhou and each of its prefectures. The results show the following: (1) there is an inverted U-shaped relationship between the urbanization and ecological environment deterioration in Guizhou, which can be described by the Kuznets curve; (2) both the urbanization and ecological environment improve with the increase in the CCD; (3) unlike the traditional urbanization path, the urbanization in Guizhou features the parallel progress of industrialization and ecological environment protection. These results prove another possibility of the Kuznets curve: the curve can reach the turning point without high urbanization. This new urbanization path of balance-upgrading provides an important reference for backward areas to realize low-carbon economy and sustainable development at the same time. [ABSTRACT FROM AUTHOR]

The planting of shrubs and trees on geogrid-reinforced slopes is an important ecological slope protection method that is frequently implemented in the rainy areas of southern China. First, this paper analyzes the soil-fixing principle of the geogrid and root system and demonstrates the feasibility of using composite vegetation of shrubs and trees to reinforce the slope with a geogrid. Using the Yushi Expressway project in Guizhou, we conducted a stability analysis of slopes under different working conditions and different reinforcement modes. We determined that the ecological protection method of combining composite vegetation with a geogrid can effectively increase the stability of slopes. The maximum displacement of the ecological slope under rainfall conditions was reduced by 82% compared with the original slope, and the overall stability was improved by 35%. Four factors affect the slope stability: the depth of shrub reinforcement, depth of anchorage of trees, distribution of trees, and spacing of the geogrids. An orthogonal analysis considering these 4 factors with 3 levels was implemented. The following optimal combination was obtained to ensure ecological protection under rainfall conditions: a shrub reinforcement depth of 0.6 m, a tree anchorage depth of 3 m, a grid spacing of 0.4 m, and a top-sparse and bottom-dense tree distribution. The combined slope protection schematic was applied to the Yushi Expressway project in Guizhou, and a strong reinforced slope protection effect was observed. [ABSTRACT FROM AUTHOR]

On July 23, 2019, a high-speed and long-runout landslide occurred in Jichang Town, Shuicheng County, Guizhou Province, China, causing 42 deaths and 9 missing. This paper used the discrete element software MatDEM to construct a three-dimensional discrete element model based on digital elevation data and then simulated and analyzed the movement and accumulation process of the landslide. The maximum average velocity of the source area elements reached 14 m/s when passed through the scraping area; meanwhile, the velocity of the scraping area elements increased rapidly. At 90 s, the maximum displacement of the source area elements reached 1358.5 m. The heat generated during the movement of the landslide was mainly the frictional heat, and the frictional heat increased sharply when the source area elements passed through the scraping area. The change of frictional heat has a certain positive correlation with the velocity of the scraping area elements. Finally, the volume of the scraping area elements was 2.4 times greater than the source area elements in the deposits. The scraping effect increases the volume of the sliding body and expands the impact area of the landslide disaster. Additionally, by setting different compressive and tensile strengths as well as internal friction coefficients to analyze the influences of their value changes on the landslide movement process, the results show that the smaller the strengths and internal friction coefficient of the model, the greater the depth and area of the scraping area, which will result in a thicker accumulation; meanwhile, the average displacement, average velocity, and heat will also increase. [ABSTRACT FROM AUTHOR]

Slope stability analysis of the mountain landforms in southwestern China has always been an important problem in the field of geotechnical engineering. The large landslide occurs in Jichang Town, Shuicheng County, Guizhou Province, China, on July 23, 2019, as the engineering background. Based on the nonlinear relationship between the soil water content, cohesion, and friction angle measured in laboratory tests, the finite element reduction problem of the double-strength parameters is only transformed into a reduction problem of water content. Then, based on the redevelopment platform in the ABAQUS finite element software, a user subroutine to specify predefined field variables (UFIELD) was written to numerically simulate the stability of the Jichang slope before the landslide. The results show that the Jichang slope is mainly composed of basalt-weathered red clay mixed with gravel of various particle sizes. The underlying bedrock is primarily the Permian Emeishan basalt with strong-to-weak weathering and a small amount of argillaceous siltstone. Due to the increase in water content caused by heavy rainfall, the strength of the soil decreased continuously. Once the critical stress state of the slope was exceeded, the plastic sliding block slipped at high speed over a long distance along the rock-soil layer interface, and along the way, it scraped out and carried away the original loose topsoil and gravel blocks, which finally piled up in the form of a debris flow. In addition, the attenuations of the cohesion and friction angle are different. When the water content is less than 25%, the reduction coefficient of the friction angle is greater than the cohesion, which shows that the attenuation of the friction angle is stronger than that of the cohesion. The opposite is true when the water content is greater than 25%. The new method of double-strength finite element reduction presented in this paper is reasonable and feasible and is more in line with the actual situation of weathered-basalt soil slope instability in heavy rainfall areas. [ABSTRACT FROM AUTHOR]

Taking the geological conditions of a coal mine in Liupanshui City, Guizhou Province, as the background. The fracture law of the roof in the coal face and the height of the "Two zones" were obtained through theoretical analysis and empirical formula calculation, and the results were verified using similar simulation experiments. Through numerical simulation were researched the stress distribution characteristics of the overlying strata on the working face under the influence of multiple faults. The results showed that in the early stage of mining, F1 undergoes activation under the influence of the main roof weighting, leading to an increase in the degree of plastic damage to the coal seam and strata behind the working face, causing a redistribution of the behind abutment pressure. Finally, under the influence of the F1 barrier effect, the vast majority of the behind abutment pressure is transferred to the lower strata of F1, leading to a continuous increase in stress concentration there. But as the working face continues to advance, the blocking effect of the roof plastic zone above the goaf on the transmission of the behind abutment pressure of the working face begins to appear and continues to increase, leading to a decrease in the peak stress at the lower strata of F1. The stress change process on the F2 side is similar to that on the F1 side, the front abutment pressure is initially distributed in the strata in front of the working face, but as the activation degree of F2 continues to intensify, it gradually shifts to the lower strata of F2, and ultimately the majority of the front abutment pressure is borne by the lower strata of F2. [ABSTRACT FROM AUTHOR]

The theoretical analysis, mechanical test, numerical simulations, and model tests are carried out on the Taoziya tunnel in Guizhou to investigate the influence law of cumulative blasting technology on directional rock breaking and fracture propagation of brittle limestone. The penetration effect of the triangular-shaped charge cover angle on the metal jet, the expansion law of the main explosion crack, and the influence of the limestone directional damage effect are explored. The results show that high-energy metal jet is formed when the initial velocity of the shaped charge cover is lower than the sound velocity of the shaped charge cover material. The values of B1 and B2 of the original rock are 22.1 and 248.76, respectively, demonstrating the mechanical properties of high strength, high brittleness, and easy fracture. The evaluation index is brittle limestone, and the directional precracking effect of shaped charge blasting technology is remarkable. When the angle of the shaped charge cover is 90°, a penetrating crack is almost consistent with the direction of the precrack generated after the explosion. Moreover, the width of the slit is approximately 2 cm. The borehole imager scans show that the rock wall in the hole is smooth and stable, the test results are consistent with the simulation results, and the angle of the shaped charge cover is 90°. The results have certain guiding significance for rock blasting technology, surrounding rock control technology, and similar directional fracturing engineering in the karst area of Guizhou province. [ABSTRACT FROM AUTHOR]

Interbedded sandstones, shales, and coal seams were formed in marine-continental transitional environments of coal measures, and the gas source of its tight sand gas has been uncertain, which hinders the progress of natural gas exploration. This article uses the Longtan tight sand gas in west Guizhou as an example to investigate the reservoir features, gas charging history, and main source rock of tight sand gas by examining thin sections, scanning electron microscopy images, X-ray diffraction results, and the fluid inclusions with burial and thermal histories and noble gas analysis. The Longtan sandstones in this study are classified as litharenites which are characterized by low compositional and textural maturities, and high clay contents, and are distinguished petrographically from conventional sandstones by the extensive existence of micropores and microfractures. The results of the homogenization temperatures of the fluid inclusions show that the Longtan tight sand gas is a single-stage accumulation which occurred during the Late Triassic. Furthermore, through the analysis of the helium and argon isotopes of noble gases, a calculation model was established for determining the shale and coal contributions to the tight sand gas. The research results show that the Longtan tight sand gas mainly belongs to the crust-derived gas, mostly from the Longtan shale-derived contribution and to a lesser extent from the Longtan coal-derived contribution. The measured 40Ar/36Ar values of the Longtan shales and coals are consistent with the forecasted 40Ar/36Ar values from the calculation model, demonstrating that the model is viable to calculate the source rock contribution to the tight sand gas. Therefore, the Longtan shales as main source rocks can generate hydrocarbons to charge neighboring tight sandstones to form tight gas accumulation in the Longtan Formation, which provides an opportunity for tight gas development in west Guizhou. [ABSTRACT FROM AUTHOR]

The content and spatial distribution of brittle minerals, such as quartz, are important factors in determining the fracture initiation mechanism induced by hydraulic fracturing in shale reservoirs. To further research the impact of quartz content in shales of the Lower Cambrian Niutitang Formation in northern Guizhou on the fracture expansion of its reservoir, 7 groups of randomly filling shale models with different quartz contents were established using rock failure process analysis (RFPA2D-flow) code for numerical test studies under seepage-stress coupling, and 5 samples were also subjected to uniaxial compression tests using the INSTRON 1346 electrohydraulic servo-controlled material testing machine (200T). The results show that the average growth rate of the compressive strength and the fracture proportion for a quartz content of 50% to 65% are 4.22 and 1.15 times higher than those for 35% to 50%, respectively. Fractures sprout, expand, and breakdown in the shale matrix or at the junctions of the shale matrix and quartz grains. The mechanical properties and pattern of the fracture extension of the shale in the physical tests are similar to those in the numerical tests, indicating the reliability of the numerical simulations. The fractal dimension curves at different stress levels are divided into three stages: flattening, increasing, and surging, and the fractal dimension value for a quartz content of 50%~65% at a 100% stress level is 1.02 times higher than that for 35%~50%. The high degree of natural fracture development in high quartz content formations in shale gas reservoirs is of some reference value for logging data. The research results provide a reference value for the content and spatial distribution of brittle minerals for the initiation mechanism and fracture propagation of hydraulic fracturing in shale reservoirs. [ABSTRACT FROM AUTHOR]

China hosts rich shale gas resources. The Longmaxi Formation (LF) in the Sichuan Basin is one of the important regions for shale gas exploration and extraction. Here, we investigate the pore structure and factors influencing the gas-bearing characteristics of the pores in the shale reservoirs in the LF. We employed scanning electron microscopy (SEM), X-ray diffraction analysis (XRD), gas content testing, gas saturation testing based on nuclear magnetic resonance (NMR), overburden porosity and permeability analysis, distribution of pore size, specific surface area (SSA) analysis, and geochemical analysis. Our results show that the organic matter of the shale in the LF in the study area is highly favorable to shale gas conditions; the brittleness of the regional shale generally increases with an increase in depth. The pores in the LF mainly include organic matter-hosted pores, intergranular pores, intragranular pores, and microfissures, with mesopores dominating. Meanwhile, the gas content also increases with an increase in depth. The pore structure in the study area is affected by organic matter content and mineral components, with the development of organic matter-hosted pores. The porosity and the SSA are positively correlated with the total organic carbon (TOC), whereas clay minerals have an adverse effect on the SSA of pores in the study area. Higher TOC and vitrinite reflectance (Ro) indicate higher gas content. It can be inferred that as the content of brittle minerals increases, particles break to form storage spaces as the depth increases, causing the gas content to increase. Higher SSA and total pore volume indicate higher volume of adsorbed gas. The bound water in rocks tends to reduce the content of desorbed gas. Our results suggest high potential for shale gas extraction in this region. [ABSTRACT FROM AUTHOR]

Hidden karst structures are developed irregularly in the Middle Permian Maokou Formation aquifer from the northern part of the Guizhou coalfield, China. Mining operations associated with the exploitation of coal seams from the lower part of the Upper Permian Longtan Formation are threatened by karst waters from the underlying strata. To improve the accuracy of water inrush risk assessment of the karst aquifer floor in the northern Guizhou coalfield, the karst fractal quantification technique is implemented. In this study, the karst aquifer of the Maokou Formation located under the floor of the No. 15 coal seam from the Honglin Coal Mine is considered as the research object. Based on the karst results predicted by geophysical exploration methods, the fractal theory is used to quantify the degree of karst development, while the risk of water inrush from the floor of the coal seam is evaluated by applying ArcGIS information processing technology combined with the vulnerability index method. The results indicate the following observations: the mean fractal dimension of karst in the study area is 1.53, the karst structures are highly developed, and the overall distribution of karst is characterized by an irregular NW-SE direction; the main controlling factors affecting water inrush from the floor of the No. 15 coal seam are expressed by the water pressure of the aquifer, the abundance of water in the aquifer, the degree of karst development, the thickness of the effective impermeable layer, the mining depth, the coal seam dip angle, and the degree of fault complexity; the areas with the highest risk of floor water inrush are predominantly concentrated in the northwestern and central parts, but there is also a risk of floor water inrush in the first mining area of the No. 15 coal seam. This study takes into consideration complex factors such as the typical karst aquifer and the hydrogeological conditions in the northern part of the Guizhou coalfield, which results in a more realistic interpretation and can provide further guidance for water control activities in the mining area. [ABSTRACT FROM AUTHOR]

Shale matrix, located at Guizhou Province, is rich in nanopores, and gas slippage takes place during shale gas development, resulting in inapplicability of the classical Navier-Stokes equation. Investigation of gas transmission mechanism in nanoscale is helpful to reach a clear understanding of shale gas production performance. On the basis of the Knudsen number, the gas flow mechanism is divided into continuous flow, slippage flow, transition flow, and Knudsen diffusion. Notably, the accurate characterization of transition flow is still challenging up to date. Although there are many established models, they either fail to cover all the flow mechanisms or contain many fitting parameters, the determination of which requires a large number of experimental and molecular simulation data, limiting application of the existing models. Therefore, establishment of bulk-gas transport model over a wide range of Knudsen number without fitting parameters is urgent. First of all, existed theoretical models are compared, and the advantages and disadvantages of previous contributions are analyzed. Weight factors of Knudsen diffusion and slippage flow are obtained, respectively, according to Knudsen's model and Wu's model. Then, a model, free of empirical coefficients, is proposed. After that, effects of pore size, reservoir pressure, and temperature on transmission capacity are investigated. As the proposed model does not contain fitting parameters and remains high accuracy over a wide range of Knudsen number, it shares broad application potential, like shale gas production prediction, reserve estimation in Guizhou Province. [ABSTRACT FROM AUTHOR]

In order to improve energy consumption structure in Guizhou province, China, the efficient development of shale gas becomes more and more important. However, the theoretical understanding, towards microscopic gas flow mechanism, is still weak and insufficient. Although many models have been established, one part of them fails to cover all flow mechanisms, and the other part contains several fitting parameters. Moreover, nanopores can be divided into circular pore and slit pore in accordance with pore geometry. For cylindrical nanopores, by fully comparing with the existed models, a new bulk-gas transport model is proposed by weight superposition of slip flow and Knudsen diffusion, in which weight factors are obtained by Wu's model and Knudsen's model, respectively. For slit pores, an analytical equation for bulk-gas flow is proposed as well, which is free of any fitting parameters. The reliability of the proposed models has been clarified. The impacts of reservoir pressure, pore scale, and gas flow mechanism on bulk-gas flow behavior in process of shale gas development are analyzed. It is found that gas transport capacity of slit nanopores is significantly higher than that of cylindrical nanopores at the same pore scale. For slit nanopores, the larger the aspect ratio, the stronger bulk-gas transmission capacity. As the established models are free of fitting parameters and can be applied into the entire K n range with sufficient accuracy, the research will greatly benefit shale gas development. [ABSTRACT FROM AUTHOR]

The mineral components play an indispensable role in shale reservoirs, and the study of their content and character are significant for the permeability impairment rate and stress sensitivity of shale reservoirs. In this study, the shale cores from the FC1 well of the Lower Cambrian Niutitang Formation in northern Guizhou were used to analyze the mineralogical composition of five samples using X-ray diffractometry and for measurement of permeability and porosity of samples by means of the FYKS-2 high-temperature overburden porosimeter with N2, and the samples were also subjected to uniaxial compression tests using the INSTRON 1346 electrohydraulic servo-controlled material testing machine (200T), thereby analyzing the effect of mineral components on the permeability impairment rate and stress sensitivity coefficient of shale. Results indicate that the permeability and porosity are negatively correlated with effective stress and clay mineral content, and positively correlated with detrital mineral content, whereas, the change of mineral composition is not obvious for porosity. Simultaneously, the permeability impairment rate and stress sensitivity factor decrease with growing quartz content and modulus of elasticity, and increase with rising clay mineral content. Additionally, the greater the brittle minerals content of shale, the more likely it is to undergo brittle damage and more crack extension during compression with predominantly elastic deformation, resulting in a lower stress sensitivity factor. Conversely, the higher is the stress sensitivity factor. The research results further deepen the understanding of mineral components on the permeability and mechanical properties of shale reservoirs. [ABSTRACT FROM AUTHOR]

In order to verify the law of coal bed gas desorption and permeability under electrothermal high-temperature field, by establishing the mathematical model of gas seepage-heat-solid coupling, and taking gas drainage working face in Guizhou as an engineering example, the characteristics of the high-temperature field of coal under different heating hole temperatures are simulated. The COMSOL software is used to simulate the high-temperature field characteristics, thermal damage, and permeability of coal under different heating hole temperatures. The numerical simulation results show the following:(1) the influence trend of a high-temperature field on coal thermal damage and permeability is consistent, when the heating temperature is higher than 600°C, the thermal damage and permeability of coal seam change suddenly and increase with the increase of temperature. (2) When the temperature of a heating hole is 200-800°C, the gas permeability in the damaged area increases with the increase of temperature. When the heating temperature is greater than 600°C, the radial and axial permeability around the heating hole will increase. (3) Compared with the experimental data obtained by the existing researchers, the simulation results of coal permeability under the electric heating high-temperature field have a high consistency with the experimental results of Junrong and others. [ABSTRACT FROM AUTHOR]

In the Liu.Pan.Shui. coal field, Guizhou Province, China, 35°∼60° steeply inclined coal seams are widely distributed, and the coal resources present are of high quality and are mostly coking coal. However, because the roof overlying rock structure is affected by the geological conditions at a large dip angle, the combined cantilever beam structure of the overlying rock near the working face and the overlying rock masonry beam structure in front of the working face have different migration laws from when the condition of the near-level coal seam is generated. The pressure has emerged with new characteristics, posing a threat to coal mine production safety. Therefore, by establishing a mechanical model of roof overlying rock structure in accordance with the characteristics of coal seam inclination, mining height, and goaf overlap in the Liu.Pan.Shui mining area and using the analytical formula of material mechanics to calculate the behavior of rock pressure, guide the roof weakening means, construction technology, and parameters. It is used to quantitatively control the transportation load of the overlying rock on the roof of the large inclination coal seam and realize the safe and efficient mining of the precious coal resources of the Liu.Pan.Shui coal field. [ABSTRACT FROM AUTHOR]

Organic-rich shales were found in the Ordovician to Silurian Wufeng-Longmaxi Formation in northwestern Guizhou province, China, which has high shale gas content revealed by field measurement. Shale gas occurrence, free gas/sorbed gas ratio, and their influencing factors are crucial for shale gas exploitation strategy. Results indicated that the Wufeng-Longmaxi shales are dominated by type I kerogen, with total organic carbon (TOC) and equivalent vitrinite reflectance (eqvRo) of 0.77%–6.98% and 2.37%–2.53%, respectively. The total porosity and permeability are in the range of 1.23%–8.43% and 3 × 10 − 4 – 2.23 × 10 − 1 mD, respectively. FE-SEM observation and correlation analysis show shale porosity is dominated by organic matter (OM) pores, followed by interparticle (interP) pores related to brittle minerals. CH4, derived from oil cracking, is the main component of shale gas, but its proportion is lower than that in Fuling and Weiyuan areas, probably due to the weak preservation condition. Desorption gas and lost gas determined by in situ desorption test are 0.42–1.54 cm3/g and 1.9–7.14 cm3/g, respectively, and Langmuir volume ( V L ) from isothermal adsorption experiment is 1.63–4.78 cm3/g. Shale gas content is positively correlated with micropore volume, mesopore volume and TOC content but negatively correlated with macropore volume and clay mineral content, indicating that methane is preferentially stored in micropores (<2 nm) and mesopores (2–50 nm) related to OMs. By comparing actual total gas content with theoretical gas content, shale gas is considered to exist primarily in sorbed state, and the free gas proportion can increase with increased TOC content, due to that OM pores with larger sizes are also main space for free gas. Combined with the two methods, it can result in accurate calculations of shale gas reserves and free/sorbed gas ratio. Based on this understanding, a model of shale gas occurrence was proposed, which can provide a reference for shale gas exploitation in normal pressure areas. [ABSTRACT FROM AUTHOR]

Objective. To investigate the relationship between body cell mass index (BCMI) and cognitive impairment in maintaining hemodialysis (MHD) patients. Methods. We collected the general materials, laboratory indexes, and physical measurement indexes of patients undergoing maintenance hemodialysis in hemodialysis centers of 20 tertiary and tertiary general hospitals in Guizhou Province from June to September 2020. The body composition was measured by bioelectrical impedance method, and the BCMI value was calculated. The subjects were divided into normal cognitive function group (score ≥27), mild cognitive impairment group (score 23–26), and severe cognitive impairment group (score <23). Two groups of people with normal cognitive function and cognitive impairment with similar baseline data (gender, age, and education) were obtained by propensity score matching (PSM). Results. A total of 2008 subjects were included in this study, including 467 cases (23.3%) in the cognitive impairment group. A total of 814 cases were accurately matched after PSM. Multivariate logistic regression analysis showed that the incidence risk of the BCMI Q1 group was 8.99 times higher than that of the Q4 group (95% CI: 5.74 ∼ 14.09, P < 0.001). ROC curve analysis showed that the best threshold of BCMI for predicting cognitive impairment in MHD patients was 9.05, the sensitivity and specificity were 71.5% and 62.7%, respectively, and the area under the curve was 0.713 (95% CI: 0.678 ∼ 0.748, P < 0.001). Conclusions BCMI is related to cognitive impairment in MHD patients and has predictive value for the onset of cognitive impairment in MHD patients. [ABSTRACT FROM AUTHOR]

In order to study the driving force of China's rapid economic development in the past ten years, the study takes Guizhou, Yunnan, and Guangxi as a case study, focusing on the big data assets exchange (GBDEx) and Beibu Gulf Economic Zone, and discusses the impact of Internet plus economic and government data and the big data system on regional economy. Finally, it is believed that the Internet and big data fully avoid the disadvantages of traffic distance between the western region and the eastern region, make full and efficient cooperation between enterprises and institutions in the central and western regions and Chinese and foreign economic entities, and strengthen the control of economic behavior from the big data level with the support of the service-oriented government. The information entropy output from the Internet big data system has led to a significant entropy reduction process in China's economic environment and a more orderly economic system, which is also an important reason for the rapid development of China's economy. [ABSTRACT FROM AUTHOR]

Global warming and climate anomalies have attracted worldwide attention. The study of global climate change has received increasing attention from all countries and fields worldwide. Paleoclimate research is an important way to understand past global change and environmental evolution and to simulate and predict future climate development. A stalagmite ND3 collected in Naduo Cave was used to reconstruct the history of local climate and environmental changes from 0.55 to 5.07 ka BP based on the data of 13 230Th ages and 642 groups of oxygen and carbon stable isotopes. First, according to correlation analysis, δ18O and δ13C were significantly correlated (correlation coefficient r = 0.308, n = 318, P < 0.001) during the 5.07–2.00 ka BP period. However, during the period of 2–0.55 ka BP, there was no significant correlation P > 0.05 . The δ18O and δ13C data indicate that the climatic environment changed asynchronously during the period of 2.00–0.55 ka BP. During the period of 5.07–2.00 ka BP, the influence of human activities was weak, and δ18O and δ13C indicate similar climatic and environmental conditions, both of which changed in the same direction (positive correlation). In other words, when δ18O was positive, it indicated weak summer monsoons and lower precipitation, which led to declines in vegetation, weakened biological activity, and decreased soil CO2 and positive δ13C. The reverse patterns were also true. Since 2.0 ka BP, the intensity of human activities and the transformation and influence of surface vegetation have increased, and native vegetation has been destroyed in large quantities. Therefore, the climatic and environmental significance indicated by δ13C and δ18O has been well demonstrated. Second, the δ18O records showed that stalagmite ND3 responded to the weak monsoon drought events of 4.2 ka BP and 2.8 ka BP in the Holocene in a discontinuous deposition manner, which brings up new directions for future research. [ABSTRACT FROM AUTHOR]

The spatial patterns, ecological risks, and sources of heavy metals (HMs), including Pb, Zn, Mn, Cu, Cd, Hg, and As in river sediments, were identified around a lead-zinc mine of Danzhai, Guizhou, China. The concentrations of selected HMs and their coefficient variations indicated that the river sediments around this typical lead-zinc mine were obviously contaminated with HMs. Anthropogenic activities had further enhanced the accumulation of HMs. The higher contents of the most common selected HMs were mainly distributed in the area close to the lead-zinc mine. Based on the combined evaluations of the single factor pollution index, geo-accumulation index, and potential ecological risk index, it indicated that the ecological risks of Hg, Cd, Zn, and Pb were high or extremely high, and of Mn, Cu, and As were slight or none in the sediments around this lead-zinc mine. It was found that lead-zinc mining and smelting activities, coal mining activities, and agricultural activities (livestock and poultry breeding) are the primary sources of selected HMs, based on the results of correlation analysis together with principal component analysis (PCA) and positive matrix factorization (PMF) model. The pollution of HMs in the river sediments around a lead-zinc mine was predominantly caused by lead-zinc mining and smelting activities. Therefore, for environmental persistence, lead-zinc mining and smelting activities should be given careful consideration and under close surveillance. [ABSTRACT FROM AUTHOR]

The mining of manganese brings excellent wealth to humankind. However, it destroys the ecological environment, mainly manifested as heavy metal pollution and vegetation destruction. The restoration of ecological vegetation in manganese mining areas has become an important work after mineral exploitation. The effect of bryophytes on ecological restoration in mining areas is irreplaceable. The bryophytes diversity and its pioneering role in two types of manganese waste residue areas were investigated in Guizhou province, China. The results showed that there were 24 species of mosses in mine waste slag areas, and all of them belonged to 6 families and 15 genera; the species Gymnostomum subrigidulum, Pohlia gedeana, and Bryum atrovirens were the dominant mosses. There were 6 species of mosses in electrolytic manganese slag areas, and all of them belonged to 5 families and 5 genera. The dominant moss was B. atrovirens. The bryophytes diversity in the electrolytic manganese slag areas with lower pH was poorer than that in mine slag areas. The accumulation of heavy metals in mosses showed that B. atrovirens collected from two types of areas had a strong ability to accumulate Mn with the cumulants 5588.00 μg/g and 4283.41 μg/g, respectively. All mosses had a strong enrichment ability to Cd. It indicated that mosses had strong tolerance to heavy metals. Bryophytes increased the available nutrients and bacterial community diversity of mosses growth substrates in two types of areas. Besides, we studied the relationships between bacterial community structure and soil factors. The main soil factor affecting the bacterial community structure was available nitrogen (AN) in mine waste slag areas, while it was pH in the electrolytic manganese residue areas. The systematic study suggested that bryophytes increased the available nutrients and the microbial community diversity of the growth substrates in manganese waste residue areas, which provided the basic conditions for the growth of vascular plants. [ABSTRACT FROM AUTHOR]

The pore structure of marine-continental transitional shales from the Longtan Formation in Guizhou, China, was investigated using fractal dimensions calculated by the FHH (Frenkel-Halsey-Hill) model based on low-temperature N2 adsorption data. Results show that the overall D 1 (fractal dimension under low relative pressure, P / P 0 ≤ 0.5) and D 2 (fractal dimension under high relative pressure, P / P 0 > 0.5) values of Longtan shales were relatively large, with average values of 2.7426 and 2.7838, respectively, indicating a strong adsorption and storage capacity and complex pore structure. The correlation analysis of fractal dimensions with specific surface area, average pore size, and maximum gas absorption volume indicates that D 1 can comprehensively characterize the adsorption and storage capacity of shales, while D 2 can effectively characterize the pore structure complexity. Further correlation among pore fractal dimension, shale organic geochemical parameters, and mineral composition parameters shows that there is a significant positive correlation between fractal dimensions and organic matter abundance as well as a complex correlation between fractal dimension and organic matter maturity. Fractal dimensions increase with an increase in clay mineral content and pyrite content but decrease with an increase in quartz content. Considering the actual geological evaluation and shale gas exploitation characteristics, a lower limit for D 1 and upper limit for D 2 should be set as evaluation criteria for favorable reservoirs. Combined with the shale gas-bearing property test results of Longtan shales in Guizhou, the favorable reservoir evaluation criteria are set as D 1 ≥ 2.60 and D 2 ≤ 2.85. When D 1 is less than 2.60, the storage capacity of the shales is insufficient. When D 2 is greater than 2.85, the shale pore structure is too complicated, resulting in poor permeability and difficult exploitation. [ABSTRACT FROM AUTHOR]

Transportation is an example of a typical, open, fluid complex network system. Expressways are one form of complex transportation networks, and expressway service areas serve as infrastructure nodes in the expressway transportation network; hence, their construction has a significant impact on tourism development and utilization. Domestic and foreign studies on complex transportation networks have mostly been conducted from the perspective of railways, air transport, and urban transportation but seldom on expressway transportation networks. This study employed complex network theory, social network analysis, kernel density analysis, and bivariate autocorrelation to characterize the spatial structure of expressway transport networks in terms of geographical centrality. By innovating the coupling of geographical centrality and passenger flow centrality in clustering, the study also quantitatively analyzed the differences between the geographical advantage and actual passenger flow advantage of China's Guizhou expressway transportation network to analyze the tourism utilization potential of expressway service areas. We found that (1) the geographical centrality of the Guizhou expressway transportation network ranged from −1.28 to 3.33, and its distribution shows a single-core, polyconcentric dispersed spatial structure; (2) the passenger-car flow rate ranged from 15,000 to 3.66 million, and its distribution showed a dual-core, polycentric dispersed structure that is weakly concentric; and (3) there was a positive correlation of 0.22 between the geographical centrality and passenger flow of the Guizhou expressway transportation network, which showed seven cluster types—"high-high," "moderately high-high," "low-high," "moderately low-high," "high-low," "moderately high-low," and "low-low"—for which seven corresponding models of tourism development were proposed. This study broadens the practical application of traffic network complexity research and provides a scientific basis for upgrading and transforming the Guizhou expressway transportation network as well as for developing composite tourism uses for expressway service areas. [ABSTRACT FROM AUTHOR]

Climate change has emerged as a significant man-made global environmental challenge marked by rising temperature. The global rising temperature is supposed to alter climatic patterns like floods and droughts, thereby affecting human life supporting system and global food production. In order to clarify the impact of weather events on agricultural production in karst landforms, this study selected the indices of the growth period of crops (start time and duration), growing season precipitation, intense precipitation, number of consecutive rainless days, and number of drought-flood abrupt alternation events to evaluate the variation trend of future weather events and their impact on crop growth in Guizhou Province, China. The results show that (1) the climate is generally getting warmer. From 2019 to 2050, the sowing period of winter wheat and rice tends to be postponed. The duration of maize and rice's growth period will be shortened, and the life cycle of wheat also emerges as having a decreasing tendency except for those from the southern region. Comparing with the mean value during 1961 to 2018, the average crop cycle length of winter wheat, summer maize, and rice was shortened. The rate of shortening of crop cycle length is faster than the value during 1961 to 2018. (2) In the next 30 years, extreme precipitation concentrates in June and mainly falls in the central and southeast parts of Guizhou Province. In addition, summer is the outbreak period of drought events and drought-flood abrupt alternation events, which has a great impact on crop's growth. This study can provide references for the planting system, structure, layout, and management of crops in the karst region. [ABSTRACT FROM AUTHOR]

Organisms that have colonized underground caves encounter vastly different selective pressures than their relatives in above‐ground habitats. While disruption of certain pigmentation genes has been documented in various cave‐dwelling taxa, little is known about wider impacts across pigmentation and other gene pathways. We here study the timeframe and transcriptional landscape of a leucistic and blind cypriniform fish (Oreonectes daqikongensis, Nemacheilidae) that inhabits karst caves in Guizhou, China. Based on data from the mitochondrial ND4,ND5, and Cytb genes, we show that the divergence between O. daqikongensis and its most closely related pigmented species occurred ca. 6.82 million years ago (95% HPD, 5.12–9.01), providing ample time for widespread phenotypic change. Indeed, we found that the DNA sequence of Mc1r (melanocortin‐1 receptor), a key gene regulating the biosynthesis of melanin in most vertebrates, is pseudogenized in O. daqikongensis, caused by a 29 bp deletion in the protein‐coding region. Furthermore, 99,305 unigenes were annotated based on the transcriptome of skin tissue of Oreonectes fish. Among the differentially expressed unigenes, 7,326 (7.4% of the total unigenes) had decreased expression and 2,530 (2.5% of the total unigenes) had increased expression in O. daqikongensis skin. As predicted, the expression of Mc1r and 18 additional genes associated with melanin biosynthesis was significantly downregulated in the skin tissue of O. daqikongensis, but not in its congener. Our results, integrating with other studies on cavefishes, suggest that loss of pigmentation was caused by coding region loss‐of‐function mutations along with widespread transcriptional changes, resulting from extended evolutionary time as a cave‐dwelling form. [ABSTRACT FROM AUTHOR]

Given the flammability of power cables and the high cost of utility tunnel construction, power cable fires cause serious economic losses and are associated with a negative social impact. In the study, a weighted fuzzy Petri net and an event tree are combined to propose a quantitative evaluation method to mitigate cable fire risks in a utility tunnel. First, cable fire risk factors are analyzed. Given the lack of utility tunnel cable fire historical data, fuzzy theory is used to calculate the failure probability of the primary event. Second, a weighted fuzzy Petri net is used for fuzzy reasoning, and an event tree is used to analyze all possible consequences. Subsequently, the numerical simulation method is used to quantify the loss from the cable fire and thereby quantify the risk of cable fire. Finally, the effect of different risk factors on a cable fire is analyzed to determine the main factors that affect cable fires. Simultaneously, the control ability of different control measures with respect to the fire is analyzed to determine key control measures. A case study of a utility tunnel cable cabin in Liupanshui in Guizhou is employed to validate the utility of the proposed method. [ABSTRACT FROM AUTHOR]

A full analysis of 3-month Standardized Precipitation-Evapotranspiration index (SPEI-3) changes and attribution analyses are of significance for deeply understanding dryness/wetness evolutions and thus formulating specific measures to sustain regional development. In this study, we analyze monthly and annual SPEI-3 changes over Southwest China (SWC; including Sichuan (SC), Chongqing (CQ), Guizhou (GZ), Yunnan (YN), and west Guangxi (wGX)) during 1961–2012, using the SPEI model and routine meteorological measurements at 269 weather sites. For SWC and each subregion (excluding wGX), annual SPEI-3 during 1961–2012 tends to decrease, and drying is at most of months in January and September–December, but wetting is in February–August (excluding March for wGX). Additionally, more than 50% of sites show declined and increased SPEI-3 in January, April, June, and August–December and the remaining months, respectively. Except for wGX with dominant of ET0, annual SPEI-3 changes in SWC and other four subregions have dominant of precipitation. Spatially, annual SPEI-3 changes at 59% of sites are because of precipitation, generally located in southeast SC, south YN, CQ, GZ, and south and northeast wGX. Nevertheless, dominants at regional and site scales vary among months, e.g., SWC, SC, CQ, and GZ, having dominant of precipitation (ET0) during September–December (most of months during January–August), YN always with dominant of precipitation, and wGX with dominant of precipitation (ET0) in February–April and July–December (January, May, and June). Importantly, this study provides a reference for quantitatively evaluating spatiotemporal dryness/wetness variations with climate change, especially for regions with significant drying/wetting. [ABSTRACT FROM AUTHOR]

In order to obtain the functional relationship of gas content and gas pressure, and to accurately calculate the two values which fitting the characteristics of coal seam, the destruction coefficient (X) and the index (ΔP) of the initial velocity of gas emission are introduced to establish the new model with higher precision based on Langmuir equation and destruction type of coal. The applicability of classic model (W-P model) and new optimization model in Guizhou mining areas are studied through the statistics of basic parameter data from 107 groups of coal-seam gas in eight mining areas. The results show that the gas content calculated by the classical model is lower than the measured value, while the gas pressure value is larger than that. The average relative error of gas content and pressure data reach 23.98% and 97.86%, respectively. The gas content and pressure data calculated by the optimization model are well fitted with the measured value. The fitting degree gradually rises with the increase of the sample size, and the average relative errors are 6.44% and 14.27%, respectively. Compared with the classical model, the average relative errors of gas content and pressure calculated by the optimization model reduce by 17.54% and 83.59%, respectively. The optimization model controls the tendency of calculated value error which significantly rises as the ΔP increases. For the coals with different destruction types, the average relative error of calculated gas content in optimization model ranges from 4.40% to 11.99%. And the average relative error of calculated pressure value ranges from 9.84% to 25.80%, both of them are far superior to that of classical model. The optimization model is more accurate for calculating the gas content and pressure in Guizhou. [ABSTRACT FROM AUTHOR]